Refrigerating apparatus



Jan. 25, 1937. 3 PENDERGAST AL 2,068,697

REFRIGERATING APPARATUS Filed Nov. 30, 1931 2 Sheets-Sheet 1 INVENTORS.

7710mm 5 Peaoakcns r.

WY M ATTORNEYS Patented Jan. 25, 1937 one arm arr xi REFRKGERATINGAPPARATUS Application November 30, 1931, Serial No. 578,049

2 Claims.

This invention relates to refrigerating apparatus and has to do withsubstantially independent means for defining a sharp freezing chamberand for controlling the temperature of the box, but supplied with thesame source of refrigerant.

The placing of sharp freezing coils and box cooling coils in series hasheretofore been attempted in several different ways, the most common ofwhich being the placing of the sharp freezing coils in a compartmentcompletely isolated from the food chamber. In the few instances we areaware of where the sharp freezing and box coils have been placed in thesame compartment some positive means has usually been provided forthermally insulating the two sets of coils from each other.

One of the objects of the present invention is the provision of asimple, compact evaporating unit which may be located as a unit adjacentthe upper part of the food chamber, and containing box cooling and sharpfreezing coils in series, the sharp freezing coils being so positionedand arranged as to have very little efiect upon the cooling of the airin the box and the box cooling coils being so positioned and of suchgreat surface area that refrigeration of the food chamber is obtainedwith very little, if any, frosting eflect.

Some other features of the invention reside in the positioning of theair cooling coils above the sharp freezing coils in such a manner as toobtain the greatest possible wiping effect between the air and thecoils, and the arrangement of the sharp freezing coils in horizontalposition and beneath the sharp freezing chamber or chambers to reducethe refrigerating effect of such coils on the air in the box to aminimum.

The air cooling coils are not only of such great surface area as toeficiently cool the air in the box without material frosting of anyportion thereof but the thermostat control is preferably positionedadjacent the air cooling coils for controlling operation oftherefrigerating systern, and for working in combination with a serieshook-up of the system to provide for automatic operation; the directresult of this arrangement and control is'that substantially all themoisture remains in the air within the box thus providing an idealstorage compartment, and a temperature control in the system dependentupon the amount of work done in the air cooling coils.

Other novel characteristics and features of the structure and systemwill be brought out in the specification and claims.

In the drawings:

Fig. 1 is a sectional view taken on line l-l of Fig. 4 and showing thecomplete unit in side elevation.

Fig. 2 is a plan view of our evaporating unit taken on line 2--2 of Fig;1 and showing in particular the manner of positioning the temperaturecontrol coil relative to any part of the air cooling coil and the mannerof connecting the same to the control unit of the system.

Fig. 3 is a front elevation, partly in section, of our novel unit shownas installed in a standard domestic refrigerator.

Fig. 4 is a fragmentary front elevation, similar to Fig. 3, but showingthe front panel for the evaporating unit in position and the door forthe sharp freezing chambers in open position.

Fig. 5 is a rear elevation of the complete unit.

It is possible to cool the food compartment of a domestic refrigeratorwith a relatively small evaporator, providing it is possible to run thesystem cold enough, but if the evaporator runs cold enough to obtainefficient cooling of the food compartment, it is obvious that themoisture in the air will condense upon the surface of the cooling unitand develop a layer of frost of such thickness as to materially lowerthe efficiency of the system. It is possible with our combinedevaporator to provide a sharp freezing chamber or chambers for freezingice cubes and the like and at the same time provide a separate portionof the evaporator for cooling the air in the food compartment withoutmaterially frosting and without material dehydration of the air withinthe compartment.

Taking up each element of the evaporating unit in its order, anexpansion valve 2 controls the inlet of refrigerant from the condensercoil 3 into the evaporator coil 4. This evaporator coil is continuousand the form and arrangement of this continuous coil plays an importantpart in the present invention.

As best shown in Fig. 5, the coil 4 extends downwardly and thenoutwardly as at 5 to the edge of the sharp freezing compartment 6. Thiscompartment 6 is merely an enclosure for preventing the drip into theice pans and while the side walls thereof are vertical, they have verysimilar to the convolutions l at the bottom of i the sleeve 6.

It will thus be seen that the sharp freezing coils l and it arepositioned almost entirely at the bottoms of the sharp freezingcompartments and thus have very little efiect upon the surrounding airin the food compartment.

The coil it is now connected by means of an extension ii into the frontend of the air cooling coil which may be generally designated Hi. Thisair cooling coil i2 is preferably in a series of longitudinalconvolutions somewhat similar to the coils l and it except that in mostcases they are preferably longer and provided with fins E3 to greatlyincrease the efiective surface area thereof. The length of the effectivesharp freezing coils l and it and the length and surface area of the aircooling coils 6'2 will vary in accordance with the sharp freezingcapacity and in accordance with the capacity of the food chamber orchambers. In other words, the size of the box may vary without changingthe capacity of the sharp freezing chambers in which case the surfacearea of the coils it will be increased, or vice versa, if any increasein sharp freezing capacity is desired. In all events, the effectivesurface area of the air cooling coils i2 is very much greater than theeffective surface area of the sharp freezing portion of the unit; infact the effective surface area of the air cooling coil is so greatrelative to the cubic foot capacity of the box that we have one set ofsharp freezing coils and one set of air cooling coils for cooling theair at a relatively high temperature without dehydration or drying. Inother words, the effective surface area of the coil 92 is so great thatheat transfer takes place between the coils and surrounding air at sogreat a volume as to make it possible to maintain the air cooling coilsat a temperature high enough to prevent frosting but low enough to keepthe box at the required temperature.

The refrigerant returns from the air cooling coils to the compressorthrough the return conduit it. The control of the entire refrigeratingsystem is by means of the unit is which may contain a switch it formanual starting and stopping and a temperature control switch ll forcontrolling the rate of freezing. A thermostatic control bulb it may beadjustably positioned at any point between the entrance ii of the aircooling coil and the return conduit l5. This bulb is connected to thecontrol unit it so as to directly control the starting and stopping ofthe entire system. By placing the thermostatic unit at some point on theair cooling coils, sufficient refrigerating effect of such air coolingcoils is made positive. The compressor will run as long as it is neededand obviously will not stop because of any pressure condition in eitherof the two sets of coils. The refrigerant flows up through the sharpfreezing c0ils,'performs its work and then flows on upinto the aircooling coils, dependent upon the amount of worl;

accept? to be done by such air cooling coils. We are thus assured ofsufiicient sharp freezing effect at all times and by locating thetemperature control at some point in the length of the air cooliii thecooling coil in the same manner as above described with reference to theattaching of the bulb it. It is important that the freezing coils arelocated on the bottom of the sharp freezing chambers so that very littleheat exchange takes place between such coils and the air in the box, andit is just as important that the air cooling surface or" the coil 82 beso greatly increased that refrigerating efiect is obtained with verylittle frosting up of the unit. Due to the arrangement of the sharpfreezing and air cooling coils in series and as one unit, and thelocating of the control on the air cooling coils, the mrm perature ofthe box is the only means for starting the system but the running periodis automatic regardless of whether the increased need for heat exchangeis in the sharp freezing unit or in the box proper, or both.

What we claim is:

l. A combined sharp freezing and air cooling evaporator for domesticrefrigerators, compris ing a continuous coil for conducting therefrigerant from and back to the refrigerating unit, the portion of saidcoil closest the condenser of the refrigerating system being arranged inclose heat exchange relation with a wallof the sharp freezingcompartment, a continuation of said coil being formed into an aircooling unit of relatively great surface area compared to the sharpfreezing portion of the coil, said air cooling unit being positionedabove the sharp freezing compartment and beingopen to free circulationof air therethrough, and means positioned adjacent the air cooling unitfor controlling the flow of refrigerant, said means being adapted foradjustable mounting at various points on said air cooling unit toregulate the temperature at which the sharp freezing and air coolingcoils are maintained.

2. A combined sharp freezing and air cooling evaporator for domesticrefrigerators, comprising a shell defining a sharp freezing chamber, arefrigerant conducting coil positioned along the bottom surface of saidshell, the sides of the shell being left free, said coil continuing froma position below the shell to a point above the shell, said coil at itsposition above the shell being provided with means for greatlyincreasing the eiiective heat exchange surface area thereof, said coilbeing formed in a series of convolutions, and a temperature control unitadjustably positioned at difierent points of said length of coil havinga relatively great surface area, to control the flow of refrigerant bythe temperature existing at the point of application of said temperaturecontrol unit.

THOMAS S. PENDERGAST. RALPH BAUM.

